How MFS formats output messages

Output messages processed by MFS are formatted based on the contents of two MFS control blocks: the message output descriptor (MOD) and the device output format (DOF).

The MOD defines output message content and, optionally, literal data to be considered part of the output message. Message fields (MFLDs) refer to device field locations through the device field (DFLD) definitions in the DOF. The device output format (DOF) specifies the use of hardware features, device field locations and attributes, and constant data considered part of the format.